Radiac® Surface Grinding Wheel, 7 in Wheel Diameter, 1/2 in Wheel Thickness, 1-1/4 in Center Hole, 60 Grit, Medium Grade, Aluminum Oxide Abrasive, 3600 rpm Maximum, Wheel Hardness: J, Vitrified Bond, Wheel Type Number: Type 1, Applicable Materials: Carbon Steel, HSS, Tool and Die Steel and other High Alloy, High Tensile Strength Materials, Brown/White Wheel, Specifications Met: ANSI B7.1, ANSI B74.2